1. Field of the Invention:
The present invention relates to a drive roller for use in a conveyor to move containers, part-storing wooden boxes or the like in a factory, storehouse, etc..
2. Description of the Prior Art:
FIG. 1 shows a well-known typical roller conveyor having rollers 100 each having a motor provided therein and which are driven and stopped by turning on and off the power supply thereto through a power line 101. The reference A in FIG. 1 indicates an object to be conveyed and 102 indicates a conveyor frame.
FIGS. 2 and 3 show another conventional roller conveyor having a frame 102 on which free rollers 103 are mounted each having a clutch mechanism 104 provided under it. The clutch mechanism 104 comprises a rotary shaft 105 on which a sprocket 106 and urethane roller 107 are fixed and which is rotatably supported at both end portions thereof in bearings 108 one of which has a lifting diaphragm 109 provided under it. The diaphragm 109 is provided with an air supply/exhaust port 110 to which an air pipe 111 is connected. The other bearing 108 is so supported in a rubber bush 112 that vertical movement of the corresponding end portion of the rotary shaft 105 can be accommodated.
A chain 113 extending around the sprocket 106 and a sprocket 115 of a motor 114 is provided. In this conventional roller conveyor, the motor 114 is put into operation to rotate the rotary shaft 105 while the diaphragm 109 is supplied with air to lift the urethane roller 107 and thus put it into contact with the free roller 103 which in turn will be rotated, thereby to move the object A.
In the conventional roller conveyor shown in FIG. 1, the drive roller has a complicated structure which leads to a high manufacturing cost. Further, since the motor is provided inside, the roller has a large outside diameter and is not suitably used in applications which need a high torque. Also, it is difficult for the same reason to design the roller structure as an explosion-proof one.
Since the clutch mechanism is provided for the roller in the conventional roller conveyor shown in FIGS. 2 and 3, the manufacturing cost is high and the height of the entire system is inevitably large, the latter resulting in excessive use of space. Also, because of the contact between the urethane roller and free roller, large torque cannot be assured. Also, it is difficult to install and maintain the roller conveyor.